/*
    * Copyright 2023 Adrian Herscu
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package dev.aherscu.qa.s3.publisher.maven.plugin.util;
  
  import java.io.*;
  import java.util.*;
  import java.util.zip.*;
  
  import dev.aherscu.qa.s3.publisher.maven.plugin.config.*;
  
  public class ManagedFileContentEncoderGZipImpl
      implements ManagedFileContentEncoder {
  
      private static final int    BUFFER_SIZE           = 4096;
      private static final String CONTENT_ENCODING_GZIP = "gzip";
      private final File          tmpDirectory;
      private final List<String>  supportedContentEncodings;
  
      public ManagedFileContentEncoderGZipImpl(final File tmpDirectory) {
          this.tmpDirectory = tmpDirectory;
          supportedContentEncodings = new ArrayList<>();
          supportedContentEncodings.add(CONTENT_ENCODING_GZIP);
          if (!tmpDirectory.exists() && !tmpDirectory.mkdirs())
              throw new IllegalStateException(
                  "cannot create directory " + tmpDirectory);
      }
  
      @Override
      public File encode(final ManagedFile managedFile) throws Exception {
          final File file = new File(managedFile.getFilename());
          File encodedFile;
          FileInputStream fis = null;
          GZIPOutputStream gzipos = null;
          try {
              final byte[] buffer = new byte[BUFFER_SIZE];
              encodedFile =
                  File.createTempFile(file.getName() + "-", ".tmp", tmpDirectory);
              fis = new FileInputStream(file);
              gzipos = new GZIPOutputStream(new FileOutputStream(encodedFile));
              int read;
              do {
                  read = fis.read(buffer, 0, buffer.length);
                  if (read > 0) {
                      gzipos.write(buffer, 0, read);
                  }
              } while (read >= 0);
          } finally {
              if (fis != null) {
                  fis.close();
              }
              if (gzipos != null) {
                  gzipos.close();
              }
          }
          return encodedFile;
      }
  
      @Override
      public boolean isContentEncodingSupported(final String contentEncoding) {
          return supportedContentEncodings
              .contains(contentEncoding.toLowerCase(Locale.ENGLISH));
      }
  }